Implement USB "flash drive" gadget

board/businesscard/rootfs_overlay/etc/init.d/S99flashdrive

@@ -0,0 +1,15 @@
+#! /bin/sh
+
+case "$1" in
+        start|"")
+                echo 1 > /sys/class/udc/musb-hdrc.1.auto/device/gadget/lun0/ro
+                echo /dev/ubiblock0_3 > /sys/class/udc/musb-hdrc.1.auto/device/gadget/lun0/file
+                ;;
+        stop)
+                echo '' > /sys/class/udc/musb-hdrc.1.auto/device/gadget/lun0/file
+                ;;
+        *)
+                echo "Usage: flashdrive {start|stop}" >&2
+                exit 1
+                ;;
+esac

board/businesscard/v1/genimage.cfg

@@ -20,6 +20,28 @@ image flash.bin {
 	}
 }
 
+image flashdrive.vfat {
+	vfat {
+		files = {
+			"George Hilliard resume.pdf",
+			"README.txt"
+		}
+	}
+	size = 96K
+}
+
+image flashdrive.img {
+	hdimage {}
+	partition businesscard {
+		partition-type = 0xc
+		image = "flashdrive.vfat"
+	}
+	// Hardcode a size here to help the ubi builder, which cannot infer a size
+	// of this image or wait until this image is built, due to the design of
+	// genimage.
+	size = 97K
+}
+
 image root.ubi {
 	ubi {}
 	partition kernel {
@@ -34,6 +56,10 @@ image root.ubi {
 		image = "rootfs.squashfs"
 		read-only = true
 	}
+	partition flashdrive {
+		image = flashdrive.img
+		read-only = true
+	}
 }
 
 image boot.vfat {

board/businesscard/v1/post-build.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+grep -q "GADGET_SERIAL" "${TARGET_DIR}/etc/inittab" \
+	|| echo '/dev/ttyGS0::respawn:/sbin/getty -L  /dev/ttyGS0 0 vt100 # GADGET_SERIAL' >> "${TARGET_DIR}/etc/inittab"

board/businesscard/v1/uboot_defconfig

@@ -10,7 +10,7 @@ CONFIG_DRAM_ZQ=0
 CONFIG_SPL_SPI_SUNXI=y
 # CONFIG_FIT is not set
 CONFIG_BOOTDELAY=0
-CONFIG_BOOTCOMMAND="setenv bootargs console=ttyS0,115200 ubi.mtd=1 ubi.block=0,root root=/dev/ubiblock0_2; sf probe 0 20000000; ubi part rootubi; ubi read ${kernel_addr_r} kernel; ubi read ${fdt_addr_r} dtb; bootz ${kernel_addr_r} - ${fdt_addr_r}"
+CONFIG_BOOTCOMMAND="setenv bootargs console=ttyS0,115200 ubi.mtd=1 ubi.block=0,root ubi.block=0,flashdrive root=/dev/ubiblock0_2 g_acm_ms.removable=1; sf probe 0 20000000; ubi part rootubi; ubi read ${kernel_addr_r} kernel; ubi read ${fdt_addr_r} dtb; bootz ${kernel_addr_r} - ${fdt_addr_r}"
 CONFIG_LOG_MAX_LEVEL=6
 CONFIG_LOG_ERROR_RETURN=y
 # CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_USE_SECTOR is not set

configs/thirtythreeforty_businesscard_defconfig

@@ -12,6 +12,8 @@ BR2_TARGET_GENERIC_ISSUE="Welcome to Businesscard Linux!"
 BR2_TARGET_GENERIC_GETTY_PORT="/dev/ttyS0"
 BR2_TARGET_GENERIC_GETTY_BAUDRATE_115200=y
 # BR2_TARGET_GENERIC_REMOUNT_ROOTFS_RW is not set
+BR2_ROOTFS_OVERLAY="$(BR2_EXTERNAL_BUSINESSCARD_PATH)/board/businesscard/rootfs_overlay"
+BR2_ROOTFS_POST_BUILD_SCRIPT="$(BR2_EXTERNAL_BUSINESSCARD_PATH)/board/businesscard/v1/post-build.sh"
 BR2_ROOTFS_POST_IMAGE_SCRIPT="support/scripts/genimage.sh"
 BR2_ROOTFS_POST_SCRIPT_ARGS="-c $(BR2_EXTERNAL_BUSINESSCARD_PATH)/board/businesscard/v1/genimage.cfg"
 BR2_LINUX_KERNEL=y